1. Field of the Invention
The present invention relates to a magnetic disc cassette apparatus wherein a flexible magnetic disc is contained in a cassette case.
2. Description of the Prior Art
As is well known, a flexible magnetic disc is usually contained in an envelope or cassette, and is called a floppy disc. The floppy disc system is frequently used as a memory system of a computer system.
If recording or reproducing of data is performed in such a magnetic disc system, dust which may invade the case will get in between the magnetic head and the magnetic disc, thereby causing a drop-out phenomenon to occur in the output signal. To prevent the occurrence of such a phenomenon, it has been proposed to provide means for removing dust from the recording/reproducing surfaces of the magnetic disc. In this case, however, an opening must be formed in the case for insertion of such dust removing means, or dust removing means must be inserted from the small aperture for insertion of the magnetic head. With this approach, however, various restrictions are encountered.
To eliminate such an inconvenience, it has been proposed to insert a non-woven sheet material into the case and allow it to sweep the recording and reproducing surface. In the case of a floppy disc cassette wherein the case is made of a soft material, the insertion of such a non-woven sheet material may have provided a sufficient sweeping effect, but in the case of a floppy disc cassette wherein the case is made of a relatively hard material, a satisfactory sweeping effect has heretofore been unattainable.